Plasma arc torch providing angular shield flow injection

Abstract

Plasma arc torches described herein include a torch tip with an improved nozzle that provides angular shield flow injection. In particular, the nozzle provides angular / conical impingement of a fluid (e.g., a shield gas) on an ionized plasma gas flowing through a plasma arc torch. Some of the torch tips described herein include a nozzle with a conical external shape combined with a shield with complementing internal geometry to form the angular fluid flow. As a result, a plasma arc torch including the improved nozzle have the benefits of a stabilized ionized plasma gas flow together with enhanced nozzle cooling and protection from reflecting slag during torch use.

Description

RELATED APPLICATIONS [0001] This application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 60 / 672,777, filed on Apr. 19, 2005, entitled “Plasma Arc Torch Providing Angular Shield Flow Injection” by Duan et al., the entirety of which is incorporated herein by reference.FIELD OF THE INVENTION [0002] The invention generally relates to plasma arc torches used for cutting, piercing, and marking metal, and more particularly to plasma arc torches that provide angular (e.g., conical) shield flow injection to a plasma arc. BACKGROUND OF THE INVENTION [0003] Plasma arc torches are widely used in the cutting, piercing, and / or marking of metallic materials (e.g., elemental metals, metal alloys). A plasma arc torch generally includes an electrode mounted within a body of the torch (i.e., a torch body), a nozzle having an exit orifice also mounted within the torch body, electrical connections, fluid passageways for cooling fluids, shielding fluids, and arc ...

AI Technical Summary

Benefits of technology

The present invention provides a plasma arc torch with a nozzle and shield that can effectively cool the torch's nozzle and protect against slag reflection. The nozzle has a conical exterior portion with a specific angle, and the shield has a conical interior portion that creates a fluid passageway between them. The torch also includes a securing mechanism for attaching the nozzle and shield to the torch body. The invention improves the stability of the plasma gas flow and provides a more stable plasma arc. The torch can be used for cutting, piercing, and marking metallic materials.

Problems solved by technology

As a result of the impingement, the ionized plasma gas flow can be disrupted (e.g., generating instabilities in the plasma gas flow), which may lead to degraded cutting, piercing, or marking performance.

However, in general, plasma arc torches that have substantially columnar flow of the shield gas and the plasma gas have difficulty cooling the tip of the nozzle and provide less protection from reflecting slag during cutting than plasma arc torches which use 90 degree impinging shield gas flow injection.

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